The present invention relates generally to fuel injection pumps of the type having a rotary charge pump with one or more reciprocating pumping plungers for sequentially supplying measured charges of fuel under high pressure to an associated internal combustion engine for fuel injection and relates more particularly to a new and improved spill control mechanism for spill control of the high pressure fuel charges.
In a fuel injection pump of the type described, it may be desirable to control the size and/or timing of each high pressure fuel charge by a spill control system providing spill control of the beginning and/or end of the high pressure fuel injection event. For example, U.S. Pat. No. 4,376,432 of Charles W. Davis, dated Mar. 15, 1983, and entitled "Fuel Injection Pump With Spill Control Mechanism", discloses a spill control system providing spill control of the end of the fuel injection event.
In accordance with the present invention, several embodiments of a spill control mechanism are provided which employ one or more rotating fuel control valves for spill control of the high pressure fuel charges. The rotating fuel control valve(s) are mounted on the charge pump rotor and connected to the charge pump for spill control of the high pressure fuel charges. The high pressure fuel charge is precisely controlled with a high degree of repeatability and reliability over a long service free life.
A principal object of the present invention is to provide a new and improved spill control mechanism of the type operable for controlling the size and/or timing of the high pressure fuel charge by spill control of the beginning and/or end of the fuel injection event. In accordance with the present invention, the spill control mechanism is compact, is useful in rotary fuel injection pumps of the type described without substantial pump modification, can be economically manufactured and provides accurate spill control for repeatable delivery of precise high pressure fuel charges for fuel injection.
Another object of the present invention is to provide a new and improved spill control mechanism of the type described which provides precise control of the size of the injected fuel charges.
Another object of the present invention is to provide a new and improved spill control mechanism of the type described for establishing high pressure pilot fuel injection phase in advance of a main fuel injection phase.
Still another object of the present invention is to provide in a fuel injection pump of the type described, a new and improved spill control mechanism useful in fuel injection systems having very high fuel injection pressures of up to 12,000 psi or more.
A further object of the present invention is to provide a new and improved spill control mechanism of the type described having an operating mechanism for adjusting the quantity of an injected fuel charge in a precise and simple manner and for varying the fuel injection timing in accordance with a change in the engine load and/or engine speed.
Another object of the present invention is to provide a new and improved spill control mechanism of the type described for adjusting the spill timing at the beginning and end of the fuel injection event.
Another object of the present invention is to provide a new and improved spill control mechanism of the type described which can be readily adapted to be operated to control the quantity and/or timing of each high pressure fuel charge supplied by the pump, for example by mechanical, electrical, hydraulic and/or vacuum operated means driven by the fuel injection pump or the associated engine.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.